Deep-sea hydrothermal vents and their associated fauna were first discovered along the Galapagos Rift in the eastern Pacific in 1977. Vents are now known to occur along all active mid ocean ridges and back-arc spreading centres, from fast to ultra-slow spreading ridges. The interest in chemosynthetic environments was strengthened by the discovery of chemosynthetic-based fauna at cold seeps along the base of the Florida Escarpment in 1983. Cold seeps occur along active and passive continental margins. More recently, the study of chemosynthtetic fauna has extended to the communities that develop in other reducing habitats such as whale falls, sunken wood and areas of oxygen minima when they intersect with the margin or seamounts.

Since the first discovery of hydrothermal vents, more than 1300 species have been described from vents, seeps and whalefalls (200 added during the course of the ChEss programme). This is equivalent of 1 new description every 2 weeks! As biologists, geochemists, and physicists combine research efforts in these systems, new species will certainly be discovered. Moreover, because of the extreme conditions of deep-water chemosynthetic habitats, certain species may have specific physiological adaptations with interesting results for the biochemical and medical industry.

C. Fisher, PSU.

C. Smith, Uni. Hawaii.

U. Bremen

C. Smith, Uni. Hawaii.

These globally-distributed, ephemeral and insular habitats that support endemic faunas offer natural laboratories for studies on dispersal, isolation and evolution. Here, hydrographic and topographic controls on biodiversity and biogeography might be much more readily resolved than in systems where climate and human activity obscure their role. In addition, hydrothermal vents have been suggested to be the habitat of the origin of life. These hypotheses are being used by ChEss researchers in collaboration with NASA to develop programmes to search for life in planets or moons of the outer space.

Objectives of ChEss

Only a small fraction of the global ridge system (~65000km) and of the vast continental margin regions have been explored and their communities described. It is the aim of ChEss to improve our knowledge on the diversity, abundance and distribution of species from vents, seeps and other reducing habitats at a global scale, understanding their the abiotic and biotic processes that shape and maintan these ecosystems and their biogeography.

Download the ChEss SciencePlan

Main ChEss Science Questions

  1. What are the species' relationships between different habitats: vents, seeps, whale falls, sunken wood and OMZs?

  2. What is the role of deep-water circulation and geographical barriers in gene flow and biogeography?

  3. What are the factors driving patterns of biodiversity in these habitats?

Objective 1. To create a centralised database (ChEssBase) of vent and seep species. ChEssBase is a web-based database that incorporates archived and newly-collected biological material. The database is geo- and bio-referenced. ChEssBase is available online and has been integrated with OBIS.

Objective 2. To develop a long-term field programme to locate potential vent and seep sites. The field programme aimed to explain the main gaps in our knowledge of the diversity, abundance and distribution of chemosynthetic speceis globally. A limited number of target areas were seleceted with specific scientific questions relevant to biogeographical issues.

The target areas have been grouped into two categories. Category I, combined areas: Area A: Equatorial Atlantic Belt region; Area B: the SE Pacific region; Area C: NZ region; Area D: the Arctic and Antarctic regions, within the International Polar Year. Category II, specific areas: 1 – The ice-covered Gakkel Ridge, 2 – the (ultra)-slow ridges of the Norwegian-Greenland Sea, 3- the northern MAR between the Iceland and Azores hot-spots; 4 – the Brazilian continental margin, 5 – the East Scotia Ridge and Bransfield Strait, 6 – the SW Indian Ridge, 7 – the Central Indian Ridge.

During the field programme, ChEss promoted the development and refinement of deep-towed, remotely operated (ROV) and autonomous underwater (AUV) vehicle technologies to locate, map and sample new chemosynthetic systems. Using optical, chemical and acoustic techniques, ChEss researchers gained a better understanding of not only biogeographical patterns, but also the processes driving these ecosystems.

Picture credits from left to right:

-- C. German, NOCS. -- IFREMER. -- C. German, WHOI. -- P. Tyler, NOCS. --

TOBI: Sidescan Sonar for the mapping of the seafloor and preliminary detection of hydrothermal plumes, NOC
Nautile: Human-occupied submersible that can descend to 6000 m water depth. Ifremer
ABE: Autonomous Benthic Explorer, WHOI
Isis: Remote Operated Vehicle, NOC

Download the ChEss 2007 Science Plan

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